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• Ergonomics is the scientific study of people and their work.
• Ergonomics involves fitting workplace conditions and job demands to employee capabilities to improve the fit between workers and their workplaces.
• A practical approach to ergonomics provides a good match between humans, machines, and the work environment.

Ergonomics Code and Assessment

• Ergonomics code: PT-326.
• Total marks: 100.
• Credit hours: 2.
• Assessment includes a final exam (60 marks), midterm (20 marks), and semester work (20 marks).
• Semester work is comprised of task analysis (10 marks) and a quiz (10 marks).

Human Machine System

• A simple ergosystem involves one human and one machine in the work environment.
• A complex ergosystem involves one human interacting with different machines or several humans using one machine.
• The human machine system consists of three main systems: the human component, the machine component, and the environment

The Human Component

• Includes all human characteristics, such as anatomical, physiological, and psychological elements.
• Senses are the means of input to become aware of the surrounding like sight, smell, taste, hearing, touch, balance, body position in space, and sense of speed.
• The brain is the main information processing center, containing low-level programs that control basic sensorimotor work activities and higher-level cognitive processes.
• Responsible for planning, decision-making, and problem-solving activities.
• Physical and mental work requires education, training, energy, and motivation.
• Psychological aspects and motivation support and sustain working behavior.
• Effectors are the systems by which information is entered into a machine or passed from one human to another, including hands, feet, and voice.

Machine Component

• Includes items like chairs, tools, and equipment that humans interact with.
• Human interaction with the machine depends on suitable controls, such as a computer keyboard or tool handle.
• The controlled process information system is the machine's basic operation, such as the central processing unit of a computer and its human control.
• The display is the output of the information system, like the screen of a computer.

The Environment

• The place and circumstances in which work is carried out, encompassing physical and social aspects.
• Physical aspects include noise, vibration, light, climate, and chemical substances.
• Social aspects include family and surrounding people like colleagues.
• Human machine interaction occurs through input, data processing, and output.

Ideal HMS Strategies

• Ergonomics enables the ergosystem to function better by improving interactions between the human component and other components.
• Most strategies focus on the human component but the other components play a role.
• There are four main strategies important in the design of an ideal HMS:
• Reducing stress.
• Designing the machines.
• Matching the job demands with the people abilities.
• Improving knowledge about their environment.
• Human error is often attributed to the design of the workspace, which does not consider human characteristics and limitations.

Four Main Strategies for HMS

• The first strategy concerns stress, either physical or mental.
• Poorly designed equipment may lead to bad posture, causing abnormal stress.
• When stress exceeds tolerance, performance and productivity decline, and the safety and health deteriorate.
• The second strategy concerns design.
• Machines and equipment should be designed with human characteristics in mind.
• Good matching between machine dimensions and human characteristics aids subjects to do their job easily, safely, and efficiently.
• The third strategy aims to match job demands with people's physical and behavioral abilities to ensure a safe and productive lifestyle.
• The fourth strategy involves educating and physically training people to improve their knowledge and awareness of their environment through proper motor learning, which is associated with practice and experience.

Benefits of Ergonomics

• Ergonomics lowers costs
• Ergonomics reduces MSD risk factors and prevent MSDs.
• Ergonomics improves productivity
• Ergonomics optimizes the work environment.
• Workstation becomes more efficient by designing a job to allow for good posture, less exertion, fewer motions and better heights and reaches
• Ergonomics improves product quality
• Ergonomic design helps you build the best possible product.
• Poor ergonomics leads to frustrated and fatigued workers that don't do their best work
• Ergonomics improves employee engagement.
• Employees notice when the company is putting forth their best efforts to ensure their health and safety.
• It makes the job more pleasant and decrease turnover.
• Ergonomics shapes a better safety culture.
• Ergonomics makes your employees' lives better.
• An ergonomics program demonstrates your company's commitment to safety and health as a core value.
• Healthy employee are your most valuable asset.
• Creating and fostering the safety culture at your company will enhance the human performance of your organization.

Work-Related Musculoskeletal Disorders (MSDs)

• Common MSD disorders includes:
• Carpal Tunnel Syndrome, Tennis Elbow, Bursitis, Ischemia, De Quervain's, Sciatica, Herniated Discs, Neck strain/disability, Tendinitis, Rotator Cuff, Neuritis, Reynaud's Syndrome, Trigger Finger, Thoracic Outle Syndrome, Epicondylitis, Back strain/disability
• MSDs affect muscles, nerves, blood vessels, ligaments, and tendons.
• Symptoms include discomfort, pain, numbness, loss of motion/flexibility, spasticity, stiff joints, swelling, tingling, inflammation, throbbing, paralysis, and burning.
• Most commonly affected areas: Back, Arms, Elbows, and Shoulders, Neck, Hands, Wrists, and Fingers, Knees, Ankles, and Feet

Risk Factors Associated with MSDs

• Dependent on work positions and postures, the frequency of task performance, and the level of required effort and duration of the task.
• Pain results from increasing stress on the body structure when there any deviation from the neutral position
• Any deviation from neutral position causes imbalance between external force and internal force because muscles have to exert more force.
• If the work-related stresses increase, the load on the body structure increases and pain will start as a protective mechanism and a sign of overuse.
• The neutral position is the safest and most efficient position during work because the joints are most efficient when they operate closest to the mid-range of the joint.
• Risk factors include:
• Exerting excessive force like Lifting heavy objects/people, Pushing or pulling heavy loads, Manual pouring materials, Maintaining control of equipment or tools
• Performing same/similar tasks repetitively job is considered highly repetitive if the cycle time is 30 seconds
• Working in awkward postures or same postures for long periods like squatting, Leaning over a counter/bending, Using a knife with wrists bent, Kneeling which can place excessive force on joint and overload muscles and tendons around the effected joint.
• Poor design which Localized pressure into the body via pressing the body/part of the body against hard or sharp edges, Using the hand as a hammer can interfere with the circulation and nerve function and cause local tissues irritation.
• Environmental factors (temperatures lighten, noise, ventilation) psycho-social issues:- anxiety or job dissatisfaction, vibration, and whole body / hand arm.

Preventing Musculoskeletal Disorders

• Improve work techniques by decreasing risk factors.
• Helpful equipment to utilize includes dollies, carts, forklifts, and platforms.
• Using vibration-reducing gloves and wearing shoulder and knee pads.
• Ensure the hand tool fits the job and reduces the applied force.
• Workers must learn about the risk factors of MSDs and how to make ergonomic changes to prevent them
• Suggest a work site stretch and flex program.
• Workers must take care of the work climate noise and temperature to avoid (extreme heat increased fatigue or extreme cold that constricts blood vessels and reduced sensitivity).
• Breaks at launch time and afternoon are important part of allowing employees time to recover from the demands both mentally and physically.
• Recovery pauses are the breaks (2-3minute/one hour) in addition to usual that may help to reduce discomfort while improving productivity.

Ergonomic Control Examples

• Working with the neck or back bent forward more than 30° for more than 2 hours per day needs to be avoided.
• solutions: Raise and/or tilt the work for better access or Use a stool for ground-level work.
• Squatting for more than 2 hours per day or Kneeling for more than 2 hours per day should be avoided.
• solutions: alternate between bending, kneeling, sitting, and squatting or use tools with longer handles
• solutions for hazardous Awkward grips design work layout to reduce hand-carrying reduce amount carried.
• Use non-pinch grip postures alternate and rotate tasks.
• Intense keying for more than 4 hours per day or Repeating same motion for more than two hours per day with hands, wrists, elbows, shoulders, or neck needs to be avoided
• solutions: Arrange work to avoid unnecessary motions, Let power tools and machinery do the work, Spread repetitive work out during the day, Change hands or motions frequently, Rotate task with co-workers if possible and take stretch pauses.
• Solutions to pressuring the localized body part is too add padding, alternate and rotate tasks.
• Avoid lifting more than 75 lbs. once/day, 55 lbs. ten times/day, 10 lbs. more than twice/minute or for more than 2 hours/day, 25 lbs. above shoulders, below knees, or at arms length more than 25 times/day

Managing for safer lifting by:

• Employee guidelines for safer lifting, Stretch before lifting, Plan the lift, check of tags on loads,
• Test load for weight and stability avoid manually lifting or lowering loads to or form a clear access.
• Alternate when physically demanding tasks are combined with necessary resting.
• High level of vibration sustained for longer 30 minutes should be prevented through adequate breaks.
• Use tools with padded grips or longer handles

Case study example

• In a workplace for computer programmers who uses his keyboard for and along time who reports loss of strength the suggestion is an adjustable wrist rest and encourage to take break.